Chapter 1
Introduction
DAS-429PCI/Mx: User’s Manual
page 1 - 15
The Expansion ROM Space is not implemented on the
DAS-429PCI/Mx
.
The Interrupt Line register indicates the interrupt routing for the PCI
Controller. The ultimate value for this register is system-architecture specific.
For
x
86-based PCs, the values in this register correspond with the established
interrupt numbers associated with the dual 8259 controllers used in those
machines. In
x
86-based PC systems, the values of 0 to 15 correspond with the
IRQ numbers 0 through 15, and the values from 16 to 254 are reserved. The
value of 255 (the controller’s default power-up value) signifies either “unknown”
or “no connection” for the system interrupt. This register is boot-loaded from the
external boot memory, if present, and may be written by the PCI interface.
1.5.12
Expansion ROM Base Address Register (XROM)
Address:
30 (H)
Power-up value:
00000000 H
Boot-load:
External nvRAM offset 70 H
Attribute
Read/Write: bits 11–31, bit 00; Read only: bits 01–10
Size:
32 bits
Bit
Bit Name
Description
11-31
Expansion ROM
Base Address
Location (R/W)
Don’t Care
01–10
Reserved
Always returns 0
00
Address Decode
Enable (R/W)
Always set to 0
Expansion ROM Base Address Register
1.5.13
Interrupt Line Register (INTLN)
Address:
3C (H)
Power-up value:
FF H
Boot-load:
External nvRAM offset 7C H
Attribute:
Read/Write
Size:
8 bits
Bit
Description
00–07
Desired IRQ#
Interrupt Line Register
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